1. Technical Field of the Invention
The present invention relates generally to routing requests in a wireless network, and more particularly to a procedure for providing the calling party number of roaming subscribers.
2. Description of Related Art
In addition to offering telephonic services, most Public Land Mobile Networks (PLMNs) offer a variety of other communication services. For example, voice mail is a service whereby any party can leave a recorded voice message for the subscriber which is stored at a voice mail center. The voice mail center is usually connected as an Intelligent Peripheral (IP) to the PLMN and is accessible by establishing a phone call to a specific directory phone number associated with the voice mail center. A party can leave a voice message for a subscriber by calling the specific directory phone number, or more commonly, be forwarded to the voice mail center when calling the subscriber's phone number. The subscriber retrieves the message by establishing a call to the voice mail center using the directory phone number. Other examples of communication services include fax mail, and customer service, which are usually connected as IPs with associated directory phone numbers to the PLMN and accessible by establishing a phone call to the directory phone number.
Some IPs require the subscriber to identify themselves and provide a password/personal identification number after establishing a call to the IP. For example, voice mail often requires the subscriber to dial the subscriber's directory phone number and a password/PIN after connecting to voice mail in order to access their messages. The foregoing is often cumbersome and tedious for the subscriber.
To alleviate this problem, many IPs automatically identify the subscriber where the mobile station belonging to the subscriber is used to access the IP, thereby allowing the subscriber to bypass the identification procedure. The foregoing is accomplished at the IP by comparing the phone number of the calling party to the directory phone number of the subscriber's mobile station. The IP determines the phone number of the calling party by examining a parameter known as the calling party number, or the "A-number". During a phone call between a calling party and a called party, a packet of information is sent to the called party. The packet of information includes technical information related to the connection and routing of the incoming phone call. One of the parameters which is optionally included in the packet of information is the calling party number. The calling party number parameter identifies the phone number of the party making the outgoing phone call. The IP uses the calling party number to determine the phone number of the calling party, and where that number is the phone number of the subscriber's mobile station, the subscriber is automatically identified.
As an additional convenience to the subscriber, the subscriber is able to dial an abbreviated number, e.g. "133", to access a particular service. The abbreviated number is translated by a serving Mobile Switching Center (MSC) to generate the directory phone number for the IP providing the particular service. The directory phone number is used as the called phone number, thereby establishing access to the particular services for the subscriber.
The key advantage of subscribing to a PLMN is the mobility of the communications services. A subscriber subscribing to a PLMN can make a phone call from anywhere within the geographic area of the PLMN. The geographic area covered by a PLMN generally covers the metropolitan area of a large city or even a sizeable portion of a state or province, thereby permitting the subscriber a substantial degree of mobility. However, a subscriber traveling to a different country is frequently beyond the range of the PLMN that the subscriber subscribes to. To provide service to the subscriber, the operators of a PLMN serving the geographic area where the subscriber is located (now referred to as the Visitor PLMN--V-PLMN) permit the subscriber to use the resources and infrastructure of the V-PLMN. The foregoing is known in the art as roaming.
Because the servicing MSC in the V-PLMN is operated by a different party and not associated with the IPs of the PLMN to which the subscriber subscribes (now referred to as the Home PLMN--H-PLMN), it is unlikely that the serving MSC in the V-PLMN is able to translate the abbreviated number received from the mobile station into the directory phone number to complete a call to an IP. Instead, the subscriber must dial the full directory phone number to access or call an IP. The foregoing is particularly cumbersome if the subscriber is in a different country where an international dialing prefix and a country code must be dialed in addition to the directory phone number.
Additionally, because the calling party number is not necessary to complete a phone call, some V-PLMNs do not include the calling party number in the packet of information that is sent to the called party for roaming subscribers. As a result, a roaming subscriber accessing services from an IP is unable to take advantage of automatic identification. Therefore, even where the subscriber uses their mobile station to access the IP, the subscriber must still go through the identification procedure to access the services. Accordingly, it would be advantageous if the calling party number is provided to the IP.
It is therefore an object of the present invention to simplify a subscriber's access to IPs.